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<h1>PuTTY User Manual</h1>
<p>
PuTTY is a free (MIT-licensed) Windows Telnet and SSH client. This manual documents PuTTY, and its companion utilities PSCP, PSFTP, Plink, Pageant and PuTTYgen.
</p>
<p>
<em>Note to Unix users:</em> this manual currently primarily documents the Windows versions of the PuTTY utilities. Some options are therefore mentioned that are absent from the <a name="i0"></a>Unix version; the Unix version has features not described here; and the <a name="i1"></a><code>pterm</code> and command-line <code>puttygen</code> and <code>pageant</code> utilities are not described at all. The only Unix-specific documentation that currently exists is the <a name="i2"></a>man pages.
</p>
<p>
This manual is copyright 1997-2024 Simon Tatham. All rights reserved. You may distribute this documentation under the MIT licence. See <a href="AppendixD.html#licence">appendix D</a> for the licence text in full.
</p>

<ul>
<li><a href="Chapter1.html#intro">Chapter 1: Introduction to PuTTY</a>
<ul>
<li><a href="Chapter1.html#you-what">1.1 What are SSH, Telnet, Rlogin, and SUPDUP?</a></li>
<li><a href="Chapter1.html#which-one">1.2 How do SSH, Telnet, Rlogin, and SUPDUP differ?</a></li>
</ul></li>
<li><a href="Chapter2.html#gs">Chapter 2: Getting started with PuTTY</a>
<ul>
<li><a href="Chapter2.html#gs-insecure">2.1 Starting a session</a></li>
<li><a href="Chapter2.html#gs-hostkey">2.2 Verifying the host key (SSH only)</a></li>
<li><a href="Chapter2.html#gs-login">2.3 Logging in</a></li>
<li><a href="Chapter2.html#gs-session">2.4 After logging in</a></li>
<li><a href="Chapter2.html#gs-logout">2.5 Logging out</a></li>
</ul></li>
<li><a href="Chapter3.html#using">Chapter 3: Using PuTTY</a>
<ul>
<li><a href="Chapter3.html#using-session">3.1 During your session</a></li>
<li><a href="Chapter3.html#using-logging">3.2 Creating a log file of your session</a></li>
<li><a href="Chapter3.html#using-translation">3.3 Altering your character set configuration</a></li>
<li><a href="Chapter3.html#using-x-forwarding">3.4 Using X11 forwarding in SSH</a></li>
<li><a href="Chapter3.html#using-port-forwarding">3.5 Using port forwarding in SSH</a></li>
<li><a href="Chapter3.html#using-serial">3.6 Connecting to a local serial line</a></li>
<li><a href="Chapter3.html#using-rawprot">3.7 Making raw TCP connections</a></li>
<li><a href="Chapter3.html#using-telnet">3.8 Connecting using the Telnet protocol</a></li>
<li><a href="Chapter3.html#using-rlogin">3.9 Connecting using the Rlogin protocol</a></li>
<li><a href="Chapter3.html#using-supdup">3.10 Connecting using the SUPDUP protocol</a></li>
<li><a href="Chapter3.html#using-cmdline">3.11 The PuTTY command line</a></li>
</ul></li>
<li><a href="Chapter4.html#config">Chapter 4: Configuring PuTTY</a>
<ul>
<li><a href="Chapter4.html#config-session">4.1 The Session panel</a></li>
<li><a href="Chapter4.html#config-logging">4.2 The Logging panel</a></li>
<li><a href="Chapter4.html#config-terminal">4.3 The Terminal panel</a></li>
<li><a href="Chapter4.html#config-keyboard">4.4 The Keyboard panel</a></li>
<li><a href="Chapter4.html#config-bell">4.5 The Bell panel</a></li>
<li><a href="Chapter4.html#config-features">4.6 The Features panel</a></li>
<li><a href="Chapter4.html#config-window">4.7 The Window panel</a></li>
<li><a href="Chapter4.html#config-appearance">4.8 The Appearance panel</a></li>
<li><a href="Chapter4.html#config-behaviour">4.9 The Behaviour panel</a></li>
<li><a href="Chapter4.html#config-translation">4.10 The Translation panel</a></li>
<li><a href="Chapter4.html#config-selection">4.11 The Selection panel</a></li>
<li><a href="Chapter4.html#config-selection-copy">4.12 The Copy panel</a></li>
<li><a href="Chapter4.html#config-colours">4.13 The Colours panel</a></li>
<li><a href="Chapter4.html#config-connection">4.14 The Connection panel</a></li>
<li><a href="Chapter4.html#config-data">4.15 The Data panel</a></li>
<li><a href="Chapter4.html#config-proxy">4.16 The Proxy panel</a></li>
<li><a href="Chapter4.html#config-ssh">4.17 The SSH panel</a></li>
<li><a href="Chapter4.html#config-ssh-kex">4.18 The Kex panel</a></li>
<li><a href="Chapter4.html#config-ssh-hostkey">4.19 The Host Keys panel</a></li>
<li><a href="Chapter4.html#config-ssh-encryption">4.20 The Cipher panel</a></li>
<li><a href="Chapter4.html#config-ssh-auth">4.21 The Auth panel</a></li>
<li><a href="Chapter4.html#config-ssh-auth-creds">4.22 The Credentials panel</a></li>
<li><a href="Chapter4.html#config-ssh-auth-gssapi">4.23 The GSSAPI panel</a></li>
<li><a href="Chapter4.html#config-ssh-tty">4.24 The TTY panel</a></li>
<li><a href="Chapter4.html#config-ssh-x11">4.25 The X11 panel</a></li>
<li><a href="Chapter4.html#config-ssh-portfwd">4.26 The Tunnels panel</a></li>
<li><a href="Chapter4.html#config-ssh-bugs">4.27 The Bugs and More Bugs panels</a></li>
<li><a href="Chapter4.html#config-psusan">4.28 The &#8216;Bare <code>ssh-connection</code>&#8217; protocol</a></li>
<li><a href="Chapter4.html#config-serial">4.29 The Serial panel</a></li>
<li><a href="Chapter4.html#config-telnet">4.30 The Telnet panel</a></li>
<li><a href="Chapter4.html#config-rlogin">4.31 The Rlogin panel</a></li>
<li><a href="Chapter4.html#config-supdup">4.32 The SUPDUP panel</a></li>
<li><a href="Chapter4.html#config-file">4.33 Storing configuration in a file</a></li>
</ul></li>
<li><a href="Chapter5.html#pscp">Chapter 5: Using PSCP to transfer files securely</a>
<ul>
<li><a href="Chapter5.html#pscp-starting">5.1 Starting PSCP</a></li>
<li><a href="Chapter5.html#pscp-usage">5.2 PSCP Usage</a></li>
</ul></li>
<li><a href="Chapter6.html#psftp">Chapter 6: Using PSFTP to transfer files securely</a>
<ul>
<li><a href="Chapter6.html#psftp-starting">6.1 Starting PSFTP</a></li>
<li><a href="Chapter6.html#psftp-commands">6.2 Running PSFTP</a></li>
<li><a href="Chapter6.html#psftp-pubkey">6.3 Using public key authentication with PSFTP</a></li>
</ul></li>
<li><a href="Chapter7.html#plink">Chapter 7: Using the command-line connection tool Plink</a>
<ul>
<li><a href="Chapter7.html#plink-starting">7.1 Starting Plink</a></li>
<li><a href="Chapter7.html#plink-usage">7.2 Using Plink</a></li>
<li><a href="Chapter7.html#plink-batch">7.3 Using Plink in batch files and scripts</a></li>
<li><a href="Chapter7.html#plink-cvs">7.4 Using Plink with CVS</a></li>
<li><a href="Chapter7.html#plink-wincvs">7.5 Using Plink with WinCVS</a></li>
</ul></li>
<li><a href="Chapter8.html#pubkey">Chapter 8: Using public keys for SSH authentication</a>
<ul>
<li><a href="Chapter8.html#pubkey-intro">8.1 Public key authentication - an introduction</a></li>
<li><a href="Chapter8.html#pubkey-puttygen">8.2 Using PuTTYgen, the PuTTY key generator</a></li>
<li><a href="Chapter8.html#pubkey-gettingready">8.3 Getting ready for public key authentication</a></li>
</ul></li>
<li><a href="Chapter9.html#pageant">Chapter 9: Using Pageant for authentication</a>
<ul>
<li><a href="Chapter9.html#pageant-start">9.1 Getting started with Pageant</a></li>
<li><a href="Chapter9.html#pageant-mainwin">9.2 The Pageant main window</a></li>
<li><a href="Chapter9.html#pageant-cmdline">9.3 The Pageant command line</a></li>
<li><a href="Chapter9.html#pageant-forward">9.4 Using agent forwarding</a></li>
<li><a href="Chapter9.html#pageant-deferred-decryption">9.5 Loading keys without decrypting them</a></li>
<li><a href="Chapter9.html#pageant-security">9.6 Security considerations</a></li>
</ul></li>
<li><a href="Chapter10.html#errors">Chapter 10: Common error messages</a>
<ul>
<li><a href="Chapter10.html#errors-hostkey-absent">10.1 &#8216;The host key is not cached for this server&#8217;</a></li>
<li><a href="Chapter10.html#errors-hostkey-wrong">10.2 &#8216;WARNING - POTENTIAL SECURITY BREACH!&#8217;</a></li>
<li><a href="Chapter10.html#errors-cert-mismatch">10.3 &#8216;This server presented a certified host key which was signed by a different certification authority ...&#8217;</a></li>
<li><a href="Chapter10.html#errors-ssh-protocol">10.4 &#8216;SSH protocol version 2 required by our configuration but remote only provides (old, insecure) SSH-1&#8217;</a></li>
<li><a href="Chapter10.html#errors-cipher-warning">10.5 &#8216;The first cipher supported by the server is ... below the configured warning threshold&#8217;</a></li>
<li><a href="Chapter10.html#errors-toomanyauth">10.6 &#8216;Remote side sent disconnect message type 2 (protocol error): "Too many authentication failures for root"&#8217;</a></li>
<li><a href="Chapter10.html#errors-memory">10.7 &#8216;Out of memory&#8217;</a></li>
<li><a href="Chapter10.html#errors-internal">10.8 &#8216;Internal error&#8217;, &#8216;Internal fault&#8217;, &#8216;Assertion failed&#8217;</a></li>
<li><a href="Chapter10.html#errors-cant-load-key">10.9 &#8216;Unable to use key file&#8217;, &#8216;Couldn't load private key&#8217;, &#8216;Couldn't load this key&#8217;</a></li>
<li><a href="Chapter10.html#errors-refused">10.10 &#8216;Server refused our key&#8217;, &#8216;Server refused our public key&#8217;, &#8216;Key refused&#8217;</a></li>
<li><a href="Chapter10.html#errors-access-denied">10.11 &#8216;Access denied&#8217;, &#8216;Authentication refused&#8217;</a></li>
<li><a href="Chapter10.html#errors-no-auth">10.12 &#8216;No supported authentication methods available&#8217;</a></li>
<li><a href="Chapter10.html#errors-crc">10.13 &#8216;Incorrect MAC received on packet&#8217; or &#8216;Incorrect CRC received on packet&#8217;</a></li>
<li><a href="Chapter10.html#errors-garbled">10.14 &#8216;Incoming packet was garbled on decryption&#8217;</a></li>
<li><a href="Chapter10.html#errors-x11-proxy">10.15 &#8216;PuTTY X11 proxy: <em>various errors</em>&#8217;</a></li>
<li><a href="Chapter10.html#errors-connaborted">10.16 &#8216;Network error: Software caused connection abort&#8217;</a></li>
<li><a href="Chapter10.html#errors-connreset">10.17 &#8216;Network error: Connection reset by peer&#8217;</a></li>
<li><a href="Chapter10.html#errors-connrefused">10.18 &#8216;Network error: Connection refused&#8217;</a></li>
<li><a href="Chapter10.html#errors-conntimedout">10.19 &#8216;Network error: Connection timed out&#8217;</a></li>
<li><a href="Chapter10.html#errors-cannotassignaddress">10.20 &#8216;Network error: Cannot assign requested address&#8217;</a></li>
</ul></li>
<li><a href="AppendixA.html#faq">Appendix A: PuTTY FAQ</a>
<ul>
<li><a href="AppendixA.html#faq-intro">A.1 Introduction</a></li>
<li><a href="AppendixA.html#faq-support">A.2 Features supported in PuTTY</a></li>
<li><a href="AppendixA.html#faq-ports">A.3 Ports to other operating systems</a></li>
<li><a href="AppendixA.html#faq-embedding">A.4 Embedding PuTTY in other programs</a></li>
<li><a href="AppendixA.html#faq-details">A.5 Details of PuTTY's operation</a></li>
<li><a href="AppendixA.html#faq-howto">A.6 HOWTO questions</a></li>
<li><a href="AppendixA.html#faq-trouble">A.7 Troubleshooting</a></li>
<li><a href="AppendixA.html#faq-secure">A.8 Security questions</a></li>
<li><a href="AppendixA.html#faq-admin">A.9 Administrative questions</a></li>
<li><a href="AppendixA.html#faq-misc">A.10 Miscellaneous questions</a></li>
</ul></li>
<li><a href="AppendixB.html#feedback">Appendix B: Feedback and bug reporting</a>
<ul>
<li><a href="AppendixB.html#feedback-general">B.1 General guidelines</a></li>
<li><a href="AppendixB.html#feedback-bugs">B.2 Reporting bugs</a></li>
<li><a href="AppendixB.html#feedback-vulns">B.3 Reporting security vulnerabilities</a></li>
<li><a href="AppendixB.html#feedback-features">B.4 Requesting extra features</a></li>
<li><a href="AppendixB.html#feedback-feature-priority">B.5 Requesting features that have already been requested</a></li>
<li><a href="AppendixB.html#feedback-workarounds">B.6 Workarounds for SSH server bugs</a></li>
<li><a href="AppendixB.html#feedback-support">B.7 Support requests</a></li>
<li><a href="AppendixB.html#feedback-webadmin">B.8 Web server administration</a></li>
<li><a href="AppendixB.html#feedback-permission">B.9 Asking permission for things</a></li>
<li><a href="AppendixB.html#feedback-mirrors">B.10 Mirroring the PuTTY web site</a></li>
<li><a href="AppendixB.html#feedback-compliments">B.11 Praise and compliments</a></li>
<li><a href="AppendixB.html#feedback-address">B.12 E-mail address</a></li>
</ul></li>
<li><a href="AppendixC.html#ppk">Appendix C: PPK file format</a>
<ul>
<li><a href="AppendixC.html#ppk-overview">C.1 Overview</a></li>
<li><a href="AppendixC.html#ppk-outer">C.2 Outer layer</a></li>
<li><a href="AppendixC.html#ppk-privkeys">C.3 Private key encodings</a></li>
<li><a href="AppendixC.html#ppk-keys">C.4 Key derivation</a></li>
<li><a href="AppendixC.html#ppk-old">C.5 Older versions of the PPK format</a></li>
</ul></li>
<li><a href="AppendixD.html#licence">Appendix D: PuTTY Licence</a></li>
<li><a href="AppendixE.html#udp">Appendix E: PuTTY hacking guide</a>
<ul>
<li><a href="AppendixE.html#udp-portability">E.1 Cross-OS portability</a></li>
<li><a href="AppendixE.html#udp-multi-backend">E.2 Multiple backends treated equally</a></li>
<li><a href="AppendixE.html#udp-globals">E.3 Multiple sessions per process on some platforms</a></li>
<li><a href="AppendixE.html#udp-pure-c">E.4 C, not C++</a></li>
<li><a href="AppendixE.html#udp-security">E.5 Security-conscious coding</a></li>
<li><a href="AppendixE.html#udp-multi-compiler">E.6 Independence of specific compiler</a></li>
<li><a href="AppendixE.html#udp-small">E.7 Small code size</a></li>
<li><a href="AppendixE.html#udp-single-threaded">E.8 Single-threaded code</a></li>
<li><a href="AppendixE.html#udp-keystrokes">E.9 Keystrokes sent to the server wherever possible</a></li>
<li><a href="AppendixE.html#udp-640x480">E.10 640&#215;480 friendliness in configuration panels</a></li>
<li><a href="AppendixE.html#udp-ssh-coroutines">E.11 Coroutines in protocol code</a></li>
<li><a href="AppendixE.html#udp-traits">E.12 Explicit vtable structures to implement traits</a></li>
<li><a href="AppendixE.html#udp-perfection">E.13 Do as we say, not as we do</a></li>
</ul></li>
<li><a href="AppendixF.html#pgpkeys">Appendix F: PuTTY download keys and signatures</a>
<ul>
<li><a href="AppendixF.html#pgpkeys-pubkey">F.1 Public keys</a></li>
<li><a href="AppendixF.html#pgpkeys-security">F.2 Security details</a></li>
<li><a href="AppendixF.html#pgpkeys-rollover">F.3 Key rollover</a></li>
</ul></li>
<li><a href="AppendixG.html#sshnames">Appendix G: SSH-2 names specified for PuTTY</a>
<ul>
<li><a href="AppendixG.html#sshnames-channel">G.1 Connection protocol channel request names</a></li>
<li><a href="AppendixG.html#sshnames-kex">G.2 Key exchange method names</a></li>
<li><a href="AppendixG.html#sshnames-encrypt">G.3 Encryption algorithm names</a></li>
<li><a href="AppendixG.html#sshnames-agent">G.4 Agent extension request names</a></li>
</ul></li>
<li><a href="AppendixH.html#authplugin">Appendix H: PuTTY authentication plugin protocol</a>
<ul>
<li><a href="AppendixH.html#authplugin-req">H.1 Requirements</a></li>
<li><a href="AppendixH.html#authplugin-transport">H.2 Transport and configuration</a></li>
<li><a href="AppendixH.html#authplugin-formats">H.3 Data formats and marshalling</a></li>
<li><a href="AppendixH.html#authplugin-version">H.4 Protocol versioning</a></li>
<li><a href="AppendixH.html#authplugin-overview">H.5 Overview and sequence of events</a></li>
<li><a href="AppendixH.html#authplugin-messages">H.6 Message formats</a></li>
<li><a href="AppendixH.html#authplugin-refs">H.7 References</a></li>
</ul></li>
<li><a href="IndexPage.html#Index">Index</a></li>
</ul>

<hr><p>If you want to provide feedback on this manual or on the PuTTY tools themselves, see the <a href="https://www.chiark.greenend.org.uk/~sgtatham/putty/feedback.html">Feedback page</a>.</p><address>
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